1. Technical Field
This disclosure relates to power-line modem networks, and more particularly, to an apparatus and method for providing clock synchronization to devices in a power-line modem network.
2. Description of the Related Art
Many household devices includes memory and built-in clocks. For example, microwave ovens, VCRs, etc. include a clock readout. Power failures (due to storms, for example) can cause these devices to lose their time. Since so many devices include different programming systems, to correct the time on all of these devices can be annoying and time consuming. In addition, clocks in these different devices tend to drift, and a user can have devices that display different times throughout the house, often differing by several minutes.
Therefore, a need exists for a synchronization method, which permits all devices at a location to be synchronized without individually programming each device. A further need exists for a synchronization method, which eliminates clock drift or time discrepancies between devices at a location.
A method of clock synchronization of a powerline modem network for a plurality of devices include providing a plurality of devices having a powerline modem and a clock. The powerline modem permits communication between the plurality of devices over a powerline network. A synchronization message is provided over the powerline network. The synchronization message includes an instruction for each of the plurality of devices to update their clock in accordance with a clock time provided in the synchronization message.
In other methods, the step of providing a synchronization message may include providing the synchronization message after an interval of elapsed time. The step of providing a synchronization message may include providing the synchronization message after a power outage. The step of providing a synchronization message may include providing a synchronization device having a back-up battery and maintaining time during a power outage. The method may include the step of updating a clock on the synchronization device by invoking an external clock source. The step of providing a synchronization message may include providing the synchronization by a computer.
A synchronization device may be provided to update device clocks on a powerline network. The synchronization device includes a plug, which connects to a powerline network and powers the synchronization device. A clock maintains time on the synchronization device. A powerline modem is coupled to the plug, which sends a synchronization message to devices with clocks in the powerline network. The synchronization message enables the devices to update their clocks in accordance with the clock of the synchronization device.
In other embodiments, a battery may be included which powers the clock of the synchronization device to maintain the time during a power outage. The synchronization device may include a timing circuit, which measures elapsed time to enable reissuance of the synchronization message. The synchronization device may include a receiver, which receives a time from an external source to update the clock of the synchronization device. The devices with clocks may include at least one of a media player, a television, an answering machine, a thermostat, a clock, a stereo, a microwave and a security system.
These and other objects, features and advantages of the present invention will become apparent from the following detailed description of illustrative embodiments thereof, which is to be read in connection with the accompanying drawings.